I have a house that was built 10 years ago with a Buckingham Slate roof. The shingle is a 12″ X 20″ with a 8 or 10″ exposure. It is a great roof. The flat portion of the roof is EDPM. The slate portion has the slope of a typical mansard roof( steep) There was not a problem until we decided to build a inground pool. Our pool contractor had installed the shotcrete without any problem. The problem came when we selected a Diamondbrite plaster product. It’s durability sold us. The disaster happened when his crew’s line became clogged as they were shooting the plaster into the pool. They increased the pump and the line burst spewing plaster all over our fine roof and house. I was not here but my contractor that was building the cabana told me ever detail. They proceeded to get on ladders ( that were not tall enough) and hose the plaster off the roof. It was a relatively cool july drizzly day. The crew chief later proceeded to get a pressure washer and attack the situation. This was a mistake as he had the wrong type nozzle. When I look up, it looks like a big worm made swerly trails on the roof. Basically, he took the 10 years of aging/patina roof the roof. What can we do, clean down to what he did, or let time take care of it. Any slate experts out there? The pool contractor was at first anxious to clean it himself, but i said no, you have done enough damage
already. I am holding his money until we can determine what it is going to take to get it back. Any ideas, linseed oil, surekleen, vanatrol?